@Razvan - Do you have any examples of the difference in the bokeh between f/1.8 and f/2 on the 35/1.8? While I trust that there is a small difference in sharpness, I find it hard to believe there would be a noticeable improvement in the bokeh just from stopping down 1/3rd of a stop.

I'd suggest to post insights about the 35/1.8 in an own thread, as it is a little off-topic in a thread about the 50/1.8G.
That way one can find the information much easier afterwards.
I'll be trying for some bokeh test-shots too on this lens and see what happens when stopping down from f/1.8 to F/2.0 - and naturally comparing that to the 50/1.4G. It's all scheduled for next week.

Have fun with the new lens, KA734! I'm sure you will not be disappointed.
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Today was "axial color day" with the new lens. Axial color also called "longitudinal CA" (loCA) render subjects in front of the plane of sharpest focus in a magenta tint and subject behind that plane in a greenish tint. The effect is reduced when stopping down the lens.
It is one of the problems that often occur with large aperture primes. Nikon's latest f/1.4 lenses like the 85/1.4G and 35/1.4G had plenty of it. It could be corrected in post, but it's not as easy to clean up as lateral CAs. CaptureNX has a routine for eliminating loCAs, but if you turn it up to 100% it is not without side-effects.

The new 50/1.8G turned out to be low on loCAs which are almost gone at f/2.8 and beyond. It is clearly better in this respect than the 50/1.4G. See the results below, 50/1.8G first, followed by 50/1.4G (this is reproduced slightly below 50%, to access the large 100% original click through the image):

On a side-note: if you look closely, you might find that there is a jump in "background-sharpness" when stopping down from f/2.0 to f/2.8 while the foreground is almost unchanged. As focus was achieved manually in live-view at f/1.8 and not altered when stopping downn this is a clear indicator of focus shift to the back.
The 50/1.4G sharpens up more regularly when stopped down.

I tried out the 1.8 and the 1.4 at the store a while back, and honestly I don't think that I'd want to spend the extra money on the 1.4. The 1.8 seems to be a smidge sharper, and of course cheaper. However, I'd want to see how these lenses actually compare in real life situations, so I'll consider renting them sometime.

Tests are proceeding according to plan, famous lasts shots being done. have to send the lens back on Monday.
The write-up of the results will take some time though plus some comparative shots with the 50/1.4G...

I'm through with testing of transmission. This is on my test plan since the Nikon DX AF-S 35/1.8G came out rendering darker images then e.g. the AF-S 35/1.4G at the same apertures by around 1/2 stop.
Well, the 50/1.8G was only very slightly darker than the 50/1.4G which might very well be down to tolerances in the aperture mechanisms. Fully open, where such differences don't play a role the 50/1.4G is 2/3 of a stop brighter in the center than the 50/1.8G, as was to be expected.
In the image corners the story is a bit different as light fall-off comes into play: at f/1.8 or f/2.0 the 50/1.4G has actually less fall-off than the 50/1.8G so corners turn out to be almost 1/3 of a stop brighter on a DX sensor.

so,it's correct to say that the F/1.4 lenses are more accurate in terms of exposure compared to their budget F/1.8 counterparts? I mean,I want to know what I should understand from this. (because I've experienced different results with different lenses,at the same apertures...btw did you know that the Tamron 17-50mm F/2.8 is darker than the Nikon 18-105mm,both at F/5.6?)

p.s. no,there really aren't distinguishable differenced between F/1.8 & F/2.0 on the 35mm in terms of bokeh. I aqsually remained with a certain comparisson in mind,that of the F/2.8 vs. F/2.0 & the lather,had much creamier bokeh. so the only thing the F/2.0 has is more sharpness & a bit more DoF & remains my favorite aperture for very difficult shooting scenarios.

As it is hard to say what is a "correct" exposure, I'd not say that one lenses has a more exact aperture mechanism than the other. What I see is some variance in the effect of stopping down which even might come from the body. The only thing that is not influenced by the aperture mechanism is the exposure measured wide open (after making sure that indeed the aperture stays wide open). And in this case the 50/1.4G gives indeed an exposure that is 2/3 EV brighter wide open than the 50/1.8G.